This invention relates to the field of divider circuits and, in particular, to analog dividers with minimized phase distortion.
Such a divider may also be termed a "variable gain amplifier" since the control voltage of the amplifier may be the "divisor" signal inverted.
One common fault in such circuits is a tendency for the output signal to include false phase information due to changes in the small signal resistance of the junctions, caused by changes in the control current. This fault is of particular significance when the divider circuit is to be used in an AM stereo receiver. In the AM sterophonic system wherein the signal can be expressed by the formula: EQU (1+L+R) cos(w.sub.c t+.phi.), where .phi.=tan.sup.-1 [(L-R)/(1+L+R)]
a typical receiver will, at one or more points in the circuit, divide a signal which contains cos .phi. by another signal such as cos .phi.. This may be termed a "correction function", since the signal which is the quotient in the division process is typically a "corrected" or exact signal such as (L-R). The accuracy of the division process is significant, therefore, since the cos .phi. signal is a function of the phase modulation of the transmitted signal and any erroneous phase-related information added to the correction signal will obviously distort the audio output signals (L,R) of the receiver.